DE1922223A1 - Magnetic recording and playback system - Google Patents

Description

PATENTANWÄLTE "\ 922223

PATENT Attorney DIPL-INCR ₁ MQLLER-BORNER . PATENT Attorney DIPL-ING. HANS-H. WEY

BERLI N-DAHLEM 33 PO D BI ELSK4ALLEE 68 8 MÖNCHEN 22 WIDENM AY ERSTRASSE TEL. 0311. 7Ä2907 TELEGR. PROPINDUS TELEX 0184057 TEL. 0811 ■ 225585 ■ TELEGR. PROPINDUS TELEX 0524244

21 842

VICTOR COMPANY OF JAPAN, LIMITED Yokohama City (Japan)

Magnetic recording and playback system

The invention relates to a magnetic recording device Playback System · In particular, the invention is concerned with a magnetic recording and playback system for devices for magnetic recording of video signals on a rotating disk-shaped or cylindrical magnetic medium and for reproducing the signals below. Use of several magnetic heads that alternate and can be moved intermittently in a predetermined cycle, whereby the magnetic recording and playback system allows the feed output,

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Feed handling, feed burst and feed reset position of the magnetic heads can be determined with high accuracy by means of a simple construction.

When magnetic heads of a device for magnetic recording and playback by linear movement of several magnetic heads or two magnetic heads z. B. on a disc-shaped or roller-shaped, rotating magnetic medium, it is generally required, the feed starting position, the feed end position, the feed burst position and the like of each magnetic head to investigate. In a magnetic recording and reproducing apparatus of this type, it is necessary to have the To determine the position of the magnetic heads with high accuracy or with an error of 100 microns in order to achieve a to bring about exact synchronization on the magnetic medium. In particular, it is necessary with high accuracy the reversal of each magnetic head in a device for so-called endless recording and playback in which the moving direction of each magnetic head in the inner peripheral area and the outer peripheral portion of the rotating magnetic medium is reversed. Known devices this Art have the disadvantage that it is not possible to precisely determine the advance positions of the magnetic heads.

The present invention avoids the aforementioned disadvantage of the known devices. The main object of the invention is to provide a magnetic recording and reproducing system which allows the feed positions of the magnetic heads to be determined accurately and reliably without the

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to increase the mechanical accuracy of the device.

Another object of the invention is to provide a magnetic recording and reproducing apparatus, which allows the exact advance positions of the magnetic heads with first display means, second display means and to determine gates to which signals are supplied which are supplied by the display means,

Another object of the invention is to provide a magnetic recording and reproducing apparatus, which allows the feed positions of the magnetic heads to be determined electronically with high accuracy by the positions of the magnetic heads in the axial direction of the rotor shafts for advancing the magnetic heads by first display means and in that the rotational angular position of the rotor shafts is indicated by second display means as well as the output signals these display means are supplied to AND gates.

Another object of the invention is to provide a magnetic recording and reproducing apparatus which can allows the exact feed positions of the magnetic heads to be effectively determined, especially in the case of so-called endless magnetic recording To determine s and playback devices, in which several magnetic heads are caused to move their direction in the inner peripheral part and the outer peripheral part of the rotating magnetic medium to reverse.

Accordingly, the invention is seen in the fact that there is a magnetic medium, a plurality of magnetic heads, the

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be kept in contact with the magnetic medium, means to the magnetic medium with a to rotate at a predetermined speed, means for recording signals on the magnetic Medium in several ring-shaped, concentric tracks and means for reproducing the signals through the Magnetic heads, each with an intermittent movement device for the magnetic heads, means for generating signals for controlling the intermittent movement device, Means for displaying the advance positions of the magnetic heads, means for controlling the control signals by means of the Output signals of the display means, and means for alternating Movement of the magnetic heads at regular intervals in an intermittent motion with high Accuracy on the magnetic medium by directing the output signals of the control means to the intermittent ones Movement devices.

In Figures 1 to 3 of the drawings, the subject matter of the invention is shown using an exemplary embodiment and explained in more detail below. Show it}

Fig. 1 is a schematic side view of an embodiment of the magnetic recording and reproducing device. to which the system according to the invention can be applied;

Fig. 2 is a schematic representation of the track pattern on the magnetic medium of the device of Fig. 1j and

Fig. 3 is a block diagram of the control circuit for the Device of Fig. 1.

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In the drawings, a magnetic medium or a magnetic disk 11 is formed by having a coating of magnetizing material on opposite sides of a large-thickness disk base plate is applied or by having two magnetic disks by inserting a cushioning material layered between these and the magnetized surfaces of the magnetic disks directed outwards. Accordingly, the magnetic medium 11 has recording and reproducing sides on its top and bottom. The magnetic disk 11 is set in rotation by a synchronous motor 12, the is operated in synchronism with the vertical sync signal of the video signal. To better understand the Invention, the mode of operation of the synchronous motor is explained, although no block diagram is available.

A video signal is first fed to a well-known sine wave generator which produces the vertical sync signal from the video signal and generates a sinusoidal voltage that is synchronous with the vertical sync signal is. This sinusoidal voltage is amplified by an amplifier and fed to the synchronous motor 12 around the magnetic disk 11 at a speed of, for example 30 rpm to rotate, which corresponds to one field of the video signal.

A known tone wheel 13 is arranged on the motor shaft of the synchronous motor 12 and generates a row of pulses in one field cycle to be supplied to various circuits. These impulses become, for example, a not shown, a goal

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Λ Γ \ O * ~ \ f * ¹ f> f * i

1 922 ζ ζ J

-6-

signal generating circuit supplied, the gate signals synchronously with these pulses and directs them to each magnetic head to switch signals that by means of the gate signals are to be recorded or played back.

A video signal is then sent on or from opposite sides of the magnetic disk, which is generated by the synchronous motor is driven by the magnetic recording and playback

w recording heads 15 and 16 recorded or reproduced, which are arranged on opposite sides of the disc 11 diametrically to each other on opposite sides of a central shaft 1 ^. The first magnetic recording and reproducing head 15 is fixedly attached to the upper part of a head holder 17, the lower part of which engages by means of a thread with a screw conveyor 19 which is directly connected to the rotor shaft of a first pulse motor 18. The second magnetic recording and reproducing head 16 is fixedly connected to the lower part of a head holder 20, the upper part of which is connected to a screw conveyor 22 in FIG

| Is engaged, which is directly with the rotor shaft one second pulse motor 21 is connected. The two screws 19 and 22 are intermittently each of the Pulse motors 18 and 21 rotated The magnetic heads 15 and 16 are linearly intermittent from the outer peripheral part moved to the inner peripheral part or vice versa on the rotating magnetic disk 11, while the screw conveyors 19 and 22 are rotated intermittently, creating annular concentric tracks on the opposite sides of the magnetic disk 11 each formed by the magnetic heads 15 and 16,

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as shown in Fig. 2 «To reverse the direction of the intermittent movement of each magnetic head and 16 becomes the direction of rotation of each pulse motor 18 and 21 reversed with the means to be followed below.

In this embodiment, the rotation angle becomes one each of the pulse motors 18 and 21 (the rotation angle of the rotor shaft for each input pulse) for one step the intermittent rotation chosen so that it is 15, so that each of the magnetic heads 15 and 16 can be moved a distance on the magnetic disk 11, the two track divisions -in four steps corresponds to the intermittent rotation or if each rotor shaft rotated 60 degrees. Accordingly, each magnetic head is moved a distance that two Track pitches with four pulses and a distance corresponding to one track pitch with two pulses. It will be understood that the provision of high accuracy apparatus in which the error of track pitches the magnetic heads is very small, an increase in the number of screw pitches of the screw conveyors and 22 by fine machining methods and an increase in the number of steps of intermittent rotation of pulse motors 18 and 21 required to advance the magnetic heads a distance, respectively corresponds to a lane judgment.

Especially if six pulses (15 ° x 6 = 90 °) are used are to cause each of the magnetic heads 15 and 16 to move a distance that one Track pitch corresponds when each pulse motor 18 and

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rotates through an angle of 90, it is possible
to provide an apparatus of high accuracy because of the error in the pitch angle of a pulse motor itself in
inverse proportion to the number of pulses is reduced.

In the case of a pulse motor of the type whose maximum pulse frequency that can be output is 1000 Hz, the response time is
one step for one pulse very short. It is possible w borrowed, the Einschrittwinke1 within 2 milliseconds
control to thereby start and stop the engine.

A phototransistor 23 for determining the movement starting position of the first magnetic head 15 is arranged in a lower position which corresponds to the movement starting position Aa
of the first magnetic head, and faces a small-diameter opening 25 formed in a first base plate 24. A phototrane transistor 26 for determining the reversal position of the first magnetic head 15 is arranged in a lower position, which corresponds to the forward thrust and reversal position Ab of the magnetic head 15, and is opposite an opening 27 with a small diameter formed in the first base plate Zk . A phototransistor 28 for determining the initial movement position and the reverse position of the second magnetic head is arranged in an upper position which corresponds to the initial movement position Ba of the second magnetic head 16, and faces a small-diameter opening 30 formed in a second base plate 29.

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A lamp 31 ', which serves as a light source, is at the bottom Arranged at the end of the head mount 17. The phototransistors 23 and 26 receive through the openings, respectively 25 and 27 determine the light beam emitted from the light source lamp 31, respectively the positions Aa and Ab. After displaying the positions, each phototransistor generates a display signal. A lamp 32, which serves as a light source is arranged at the upper end of the head mount 20. The phototransistor receives through the opening 30 the light beam emitted by the light source lamp 32 is sent out and determines the position Ba. After displaying the position, the phototransistor generates 28 a display signal.

Rotary plates 35 and 36, each having small-diameter openings 33 and "} k , are mounted on the screw conveyors 19 and 22 for rotation as a unit, respectively. Rotary position indicator transistors 37 and 38 and light source lamps 39 and 39 are opposed to each other on the rotary plates 35 and 36, respectively The openings 25, 27, 30, 33 and 3k have a diameter of about 0.6 mm. The distance between the center of the rotary plates 35 and 36 and the small openings 33 and 3 ^ is each about 20 mm.

The phototransistors 37 and 38 receive the light emitted by the lamps 39 and kO and each generate a display output signal when the small openings 33 and 34 lie on the line connecting the phototransistors 37 and with the lamps 39 and kO , respectively. The rotating plates 35 and 36 are each attached to the

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port snails 19 and 22 attached so that the small Openings 33 and 34 formed in the rotary plates 35 and 36, respectively, on which the lamps 39 and 40 each with the phototransistors 37 and 38 connecting Line are when the worms 19 and 22 are rotated by a predetermined angle of rotation · The output signals generated by the phototransistors 23 and 26 become AND gate circuits 41 and 42 b passed through the output terminals a and b, respectively, as shown in FIG. 3. At the same time the output signal of the phototransistor 37 to the AND gate circuits 41 and 42 passed through the output terminal c. The output signals of the phototransistors 28 and 38 are to an AND gate circuit 43 each via the Output ports b and e routed. The AND gates 41, 42 and 43 generate an output signal

The output signals of the AND gates are fed to a pulse motor control device 45 which controls pulses of a pulse generator by means of control pulses which are supplied via an external connection f. The pulse f motors 18 and 21 are caused by the output signals of the pulse motor controller 45, for example to reverse the direction of motion or to stop.

In particular, pulses of the pulse generator 44 are from Pulses of the external terminal f controlled and each to a first and second pulse motor drive amplifier 46 and 47 headed. The output signals of these amplifiers 46 and 47 are connected to the ports g and h, respectively Pulse motors 18 and 21 passed so that the pulse motors 18 and 21 operated and in either direction from

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these output signals are set in rotation

2 shows the track pattern formed on the magnetic disk 11. A field or field of a video signal is from the first magnetic head 15 on a track a .. at the Underside of the magnetic disk 11 recorded, which rotates in the direction of arrow X. Then the current carrying the signal to be recorded is instantly applied to the second magnetic head 16 switched, which has a track a .. ' forms on the top of the magnetic disk 11.

The first magnetic head 15 is thus moved from the track a .. to a position which is removed therefrom by a distance corresponding to two track pitches, while the second magnetic head 16 performs a recording function. As soon as the track a .. 'is formed on the disk 11 by the second magnetic head 16, the current which carries the signal to be recorded is switched to the first magnetic head 15, which forms a track a ". In the same way, the second magnetic head moves to a new position while the track a "is recorded by the first magnetic head 15 and forms a track a"'as soon as the formation of the track a _{2 is} completed. This cycle is repeated so that the tracks a "(a ') ..... a _Λ

3 3 n-1

(a ' ₁ ] |, a (a,) are successively formed from the outer peripheral part to the inner peripheral part of the magnetic disk 11. When the magnetic heads 15 and 16 are respectively on the magnetic tracks a .. (a.,,) .... a-1 (a, ₁ ), the pulse generator kk generates four pulses, and when the magnetic heads 15 and 16 are in the predetermined inner circumferential positions respectively drawn by the tracks a (a _t ), the pulse generator kk generates two pulses The pulse motors 18 and 21 are like this

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designed to move the magnetic heads 15 and 16 a distance corresponding to two track pitches when four pulses are applied to them and a distance corresponding to one track pitch when two pulses are applied to them (a,) the magnetic heads 15 and 16 move to a position distant from the tracks a (a,) by a distance corresponding to one track pitch, and form the tracks b .. (b ..,), respectively. While the W magnetic heads are in these positions, the pulse generator kk generates reverse control pulses to cause the pulse motors 18 and 21 to reverse the direction of rotation. Then the pulse generator kk generates four pulses, each for the magnetic heads 15 and 16, to cause the magnetic heads to operate to move a distance corresponding to two track pitches from the inner peripheral part to the outer peripheral part of the magnetic disk 11 and form the tracks b_ (b_,) «... b (b,) as shown in broken lines . The magnetic heads reverse the direction of movement and continue intermittent movement.

Since the tracks b .. (b ..,) are each separated from the tracks a (a,) by a distance which corresponds to a track division, it follows from FIG. 2 that the tracks b _? (b ",)." .. b (b,), which are successively formed from the inner peripheral part to the outer peripheral part of the magnetic disk 11, between the tracks a * ( ^a - «i) τ ... a _n (a, ), which are each successively formed from the outer peripheral part to the inner peripheral part of the magnetic disk 11.

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When the magnetic heads 15 and 16 successively moving a distance corresponding to two track pitches reach the predetermined outer circumferential positions respectively indicated by the tracks b (b,), the pulse generator kk generates two pulses in the same manner as in the previous function, whereby the magnetic heads 15 and 16 are brought into the positions indicated by the tracks a .. (a ..,) by a distance corresponding to a track pitch. While the magnetic heads are in these positions, the pulse generator kk generates reverse control pulses to cause the pulse motors 18 and 21 to reverse their rotation. Thereafter, the pulse generator kk generates four pulses, each for the magnetic heads 15 and 16, to cause the magnetic heads to move from the outer peripheral part to the inner peripheral part of the magnetic disk 11, and respectively to create tracks a "(a ₂ ,), a"(&",) ··.· to build. The same operation is repeated and the recording operation is continued until all of the information signals to be reproduced are recorded on the magnetic disk 11.

When the magnetic heads 15 and 16 have returned from the inner peripheral part to the outer peripheral part of the magnetic disk 11 and generate signals again on the tracks ^a 1 ( ^a -ii) » ^a 2 ( ^a pi) · ■ * ·, magnetic erase heads k8 and ^ 9 are moved in front of the magnetic heads 15 and 16 respectively by forming a corresponding unit, while they are held in contact with the lower side and the upper side of the magnetic disk 11 by suitable means and are operated in such a way that they are already on the magnetic

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disc delete recorded signals. after the If old signals have been deleted, the magnetic heads 15 and 16 draw, the magnetic erase heads 48 and 49 respectively follow, new signals on the magnetic disk 11.

The operation of the embodiment will now be explained. Since the magnetic heads 15 and 16 video signals on the magnetic disk 11 by initiating their intermittent Record movement alternately from the normal movement starting positions Aa and Ba, as mentioned above the consecutive tracks a., aj, ....

a, a, and b ,, b ,, .... b, b, on top and η η '11' η η *

the underside of the magnetic disk 11 is formed. The first magnetic head 15 starts from position Aa first and then the magnetic head 16 starts alternately from the position Ba intermittent movement to the inner peripheral part of the magnetic disk 11, the first magnetic head 15 the tracks a ... ". · A and b., second magnetic head 16 the tracks a .., .. · b forms. When the first magnetic head 15 reaches the reverse feed position Ab, the phototransistor receives 26 the light beam emitted from the lamp 31 attached to the lower end of the head mount 17 which holds the first magnetic head 15 and generates a display output. This output signal is applied to AND gate 42 along with a display output generated by phototransistor 37. A control signal is from the AND gate generated by gating the received output signals and passed to the pulse motor controller 45. After the second magnetic head 16 has completed its movement

b η and the ι a
η and ^b 1 «

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ends, the direction of rotation of the pulse motors 18 and 21 is reversed from the output of the pulse motor controller 45. At the same time, the order in which the magnetic heads 15 and 16 are moved is also reversed. Thus, the second magnetic head first and then the first magnetic head 15 start alternately intermittent movement from the inner peripheral portion to the outer peripheral portion. During this movement, the magnetic head 16 forms the tracks a ... · <, <> A and b ₁ ... ob and the first magnetic head 15 the tracks a ₁ , ·. ·· ^a _n i ¹ ^ ^{10 h} i ι · ··· ^b _n i ·

When these two magnetic heads 15 and 16 are each the movement starting positions Reaching Aa and Ba, the phototransistor 28 receives the light beam emanating from the lamp is sent out, which is arranged at the upper end of the head mount 20, which carries the magnetic head 16, the Position Ba before the arrival of the magnetic head 15 in position Aa achieved. Thus, the phototransistor 28 produces a display output. The display output becomes the AND gate 43 along with the display output of the phototransistor 38 is conducted. A control signal will from AND gate 43 by gating the display outputs generated and to the pulse motor control device 45 headed. After the first magnetic head 15 has completed its movement, the direction of rotation becomes Pulse motors 18 and 21 by the output of the pulse motor control device 45 vice versa. At the same time, the order in which the magnetic heads 15 and 16 are moved, also vice versa. Thus, the first and then the second magnetic head 16 start one alternately intermittent movement against the inner peripheral part of the magnetic disk 11.

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From the foregoing I can see that through repentance the direction of movement of each magnetic head after one of the magnetic heads 15 and 16 that of the other magnetic head follows that the intermittent movement has been completed, and by reversing the sequence of movement of the magnetic heads, the direction reversal positions of the plurality of magnetic heads are never shifted from the predetermined positions. Even by changing the order of movement of the two magnetic heads from the outer peripheral part to the inner one

In the peripheral part of the movement of the magnetic heads from the inner peripheral part to the outer peripheral part of the magnetic disk, it is possible to make the order of the movement of the magnetic heads in a reverse reproducing operation coincide with the order of the movement of the magnetic heads in a normal reproducing operation. Accordingly, when the pulse motors 18 and 21 rotate in the normal direction, the first magnetic head 15 is moved in front of the second magnetic head 16 and the reverse position is indicated by the phototransistor 26, when the pulse motors 18 and 21 rotate in a reverse direction, the moves second magnetic head 16 before

k first magnetic head 15 and the reverse position is of the Phototransistor 28 displayed.

In the system according to the invention, an approximate feed position of the magnetic head 15 is shown in front of the first display means found that consist of the lamp 31 and the photo transistors 23 and 26 and an approximate advance position of the magnetic head 16 is detected by the other first indicating means coming from the lamp 32 and the phototransistor 28; a more accurate one

9 0 3 8 A 6/1 1 1 9

The advance position of the magnetic head 15 is determined by the second Determined display means, which consist of the lamp 39 and the phototransistor 37 and a more precise feed position of the magnetic head 16 is indicated by the second display means which consist of the lamp 4o and the phototransistor 38. When the display output signals, which are generated by the two display means for each magnetic head are available simultaneously stand, they are led to the AND gates 41, 42 and 43, generate the display output signals for an exact feed position. The present invention enables it, the advance position of the magnetic head 15 or 16 with high accuracy without increasing the mechanical accuracy of the device · While the magnetic heads 15 and 16 alternate intermittent movement run between their outer and inner circumferential layers, the small openings 33 and 34 of the Respective rotating plates 39 and 40 each with the lamps 39 and 40 and the photo transistors 37 and 38 per revolution of the rotary plates 35 and 36 in line so that each phototransistor 37 and 38 have a display output generated. However, it will be from the phototransistors 23t 26 and 28 generated no display signals, so that no outputs from AND gates 41, 42 and 43 can be generated.

The accuracy with which the position is determined can be increased by increasing the distance between the small openings 33 and 34 and the axes of rotation of the respective rotary plates 35 and 36 .

The present invention is very effective because it is

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enables the advance position of the magnetic heads 15 and 16 accurately determine when the speed of movement the magnetic heads is reduced.

It is understood that the system according to the invention Can be built into a device in which a roller or belt-shaped magnetic medium is used, and that the system can also be used for a device in which disk-shaped, roller-shaped or the like « magnetic media can be used for multiple channels at the same time.

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Claims (5)

Claims 1. Magnetic recording and playback system, marked through a magnetic medium, several magnetic heads that are in contact with the magnetic Medium held, means to move the magnetic medium at a predetermined speed in To displace rotation, means for recording signals on the magnetic medium in several annular, concentric tracks and means for reproducing the signals through the magnetic heads, one for each intermittent movement device for the magnetic heads, means for generating signals for control the intermittent movement devices, means for displaying the feed positions of the magnetic heads, Means for controlling the control signals by means of the output signals of the display means, and means for alternating movement of the magnetic heads in regular Distances in an intermittent movement with high accuracy on the magnetic medium by directing the output signals of the control means to the intermittent movement devices. 2. System according to claim 1, characterized in that the magnetic medium is disk-shaped _o System according to claim 1, characterized in that the magnetic medium is cylindrical. 4. System according to claim 1, characterized in that the number of magnetic heads and intermittent 9 0 V. H L 6/1 1 1 9 Moving devices is two, and that each intermittent moving device is a pulse motor (18,21) contains and a screw conveyor (19,22) which is connected to the rotor shaft of the pulse motor is, and a headgear (17.2O), the one the magnetic heads (15,16) carries, the middle »of a thread is in engagement with the transport screw 5. System according to claim 1, characterized in that W the means for displaying the advance positions of the magnetic heads (15,16) first display means (23,26,28,31,32) in the axial direction of the screw conveyor (19,22), second Contain means (37,38,39,4o) for displaying the angle of rotation of the transport screws (19,22) and AND gates (41,42,43) which receive the display output signals of the first and second display means and generate display output signals, when the display output signals of the two display means are available at the same time. 6 · System according to claim 5 »characterized in that the first display means contain a lamp (31,32) which is attached to one of the head mounts (17,2O), and a phototransistor (23,26,28) which are in With respect to the outer circumferential area of the magnetic disk 11 face a small opening (25,27,30), and that the second display means comprise a rotating plate (35,36) with a small opening (33,34) which is attached to one of the screw conveyors ( is 19,22) rotatably mounted with this as a unit, and a phototransistor (37,38), and a lamp (39,4o), and that the phototransistor and the lamp · Zwiachenführung each other at the rotating plate {35,36) 9 0 9 8 A 6/1 1 1 9 opposite so that the phototransistor and the lamp in front of the small opening (33 »3 * 0 in the Turntable can be arranged. 9098A6 / 1119 Blank page